It's a Fallacy
by RaisingCainRight
Summary: Sherlock shows off his public school education and Moriarty picks it up too quickly. AU Reichenbach, might have been Johnlock if not for. . . Well.
1. Chapter 1

**_First time on FF, folks, so reviews, tips, follows, favorites, ANY ACKNOWLEDGEMENT AT ALL would justify my continued existence!_**

**_Disclaimer: You would already know if I really owned these characters. . . _**

**_Kudos: Based on the fantastic short story by Max Shulman and the Reichenbach transcript episode so lovingly provided by St. Ariane on LJ_**

**_Ok, shutting up now. Enjoy? _**

* * *

Logical. I had to remain logical. Being logical had always saved me.

"Ah. Here we are at last," Jim Moriarty practically purred, raising his phone as though he would toss it to the pavement below. "You and me, Sherlock, and our problem – the final problem."

Logical. Collected. Keen. In my mind the words replayed themselves like a pedantic mantra, a repetition that I would find maddening in any other scenario but that in this case provided a reassuring refrain. Calculating, perspicacious, acute, and astute – I was all of these. _I would survive._

"_Stayin' alive_!" Moriarty intoned, adding, "It's so boring, isn't it? It's just – _staying_."

My brain was as powerful as a dynamo, as precise as a chemist's scales, as penetrating as a scalpel. I _would _walk away from this, and I could barely keep an uncharacteristic grin from creeping across my face. Pace. Pace. Pacing would keep the energy pent up until it was time for the revelation.

"All my life I've been searching for distractions," the once self-proclaimed IT man moaned. "You were the best distraction and now I don't even have _you_."

Keep pacing. It is not a given that the superior intellect can remain calm under the plethora of options presented by pressure. Take, for example, the man seated before me in that maddening attitude of mock despair.

"I've beaten you," Moriarty concluded smugly. And, oh, yes – _incorrectly_.

Approximately the same age as me, judging by the ratio of height to weight and the shade of natural color at the tip of those hair roots he couldn't quite reach. Approximately the same type of intelligence and level of intellect as me, judging by the way he had anticipated the way my mind would work and accounted for every step I would take. And yet. . . overall, nothing worthwhile in that overinflated head.

"And you know what?" he continued, in a tone he probably thought was teasing. "In the end it was easy."

This farce of a set-up said emotional type. Unstable. Impressionable. Worst of all, a braggart. Boasting, I submit, is the very negation of reason. To be swept up in the emotion of doing something well, to surrender oneself to ridiculous posturing simply because the next person lacks the intellect to follow your reasoning – that, to me, is the acme of mindlessness.

"Now I've got to go back to playing with the ordinary people," he spat. "And it turns out _you're_ ordinary just like all of them."

Though of course it does not count as boasting if the next person is one's catalyst, channel, conductor of light.


	2. Chapter 2

_**That was the worst chapter break I have ever done, and I apologize. Ok, let's see how the Fall would turn out if approached strictly logically. . . **_

* * *

"Ah well," Jim Moriarty said, standing up to begin pacing himself. "Did you almost start to wonder if I was real? Did I nearly get you?"

The man was ludicrous. "Wrong," I said, just as smugly as he had done a moment before.

That stopped him. "Wrong? Honey, you've been outdone at every turn, and it's time you ad_mit _that."

His reasoning was pathetically pedestrian, and I was only too happy to tell him so.

"Richard Brook," I said. "'Rich' is short for 'Richard," and 'Rich Brook' in German is 'Reichen Bach' – the case that made my name. Your first mistake. Dicto Simpliciter."

His pacing slowed, slowed, stopped. The words formed themselves in his mouth, and I could see Moriarty hating himself before they ever escaped. "I- I don't understand."

"I didn't expect you to." This felt surprisingly – _good_. "Dicto Simpliciter: an argument based on an unqualified generalization. For example: intelligence has been assigned an average number. You were assigned a number higher than that, and therefore you assume you are smarter than the average person."

"I am," he preened.

"No," I said, almost excited. He really hadn't seen this before? "The argument is a fallacy. _You are smarter _is an unqualified generalization. How many types of intelligence are there? Were you tested for all of them? Which one are you basing this assumption on? You must _qualify _your generalizations, otherwise" – I spread my arms for effect – "Dicto Simpliciter."

"Rhetoric." Moriarty's brow furrowed. "I never took that class. There was no point to it."

Was he really going to make this so easy?

"Hasty Generalization," I said gleefully. "You don't recognize the words, but you do realize the etymology is Latin. You know the Roman orators were renowned for their rhetoric, and therefore you conclude that I must be flaunting rhetoric."

"Aren't you?" he asked, almost curiously.

"Classical logic," I corrected with some disdain. "Your inference is a fallacy because it's a generalization of haste. You had too few instances to support such a conclusion."

"_My _conclusion is wrong? Sherlock, I'm disappointed." Moriarty began pacing again, his arms crossed behind his back and his hands clasped, fingers beginning to tap against his wrists.

"Try not to be utterly ridiculous," I told him, noting the patterns he tapped, repetitive of the ones he had tapped during his recent visit to my – no, _our _flat. "I am the one who should be disappointed. After all, you are now indulging in a pedestrian case of Post Hoc."

Moriarty stopped, standing stock still as his fingers paused mid-beat. I knew he was listening. He couldn't have helped it.

"Fallacy of connection," I told him, pitching my voice to imitate the surprisingly treble Russian assassin who had taken the flat upstairs. " 'Let's not go near Sherlock, though he has a computer code that can break into any system. Every time someone approaches him, they die.' "

He answered in spite of his better judgment. "I told all my clients, last one to Sherlock is a sissy."

"Idiots," I said, contempt seeping into my voice despite my half-hearted efforts to restrain it. "It's a fallacy. They don't die because they come near me – they die because someone _sees_ them come near me. If they'd thought to try cyber-threats, or blackmail. . ."

No. Not that. Not good. The last time anyone had blackmailed me, the attempt had involved bombs strapped around a man's chest and hateful red sights dancing across his haunted face, and for the slowest second of my entire life I had known that I was going to lose something irreplaceable to the laughing devil in front of me. . .

Suddenly I was in no mood to play with Jim Moriarty any more. How could I have allowed myself to lose sight of the reason I was here, or – or the answer that my logic had finally given me last night?

"Indulge me a moment longer and I'll point out one more fallacy for you," I told him shortly. "Let's try Contradictory Premises."

Perhaps the old idiom of "eyes burning holes through you" had some truth to it. Moriarty finally turned to face me, and he glared as though my face were a flint he intended to strike sparks from.

"It bears an example," I said, forging ahead when he made no answer. "If an omniscient man knows everything, can he know that he's made a mistake?"

"Of course," Moriarty spat.

"No," I said grimly, taking a step toward him and tucking my hands away inside my coat pockets to resist their urge toward violence. "If that man truly is omniscient, how could he have made the mistake in the first place? He would have known the correct process in the first place. If there is an all-encompassing knowledge, there can be no immovable problem. See the fallacy?"

Unexpectedly, Moriarty threw back his head with a laugh made the more shocking by its suddenness. "God, Sherlock, you do amuse me. That is your weakness, you know – you always want everything to be clever. Now, shall we finish the game? One final act. Glad you chose a tall building – nice way to do it."

Wait – what was he talking about? "Do it? Do – do what?"

Oh. The neatest, most logical end to his pretty story. "Of course – my suicide."

He nodded with delight. " 'Genius detective proved to be a fraud,'" he proclaimed, mimicking a tabloid headline before returning to his normal tone. "I read it in the paper, so it must be true. I love newspapers. Fairytales. And pretty Grimm ones too."

I had known it would come to this, and I knew that my logic would let me walk away, but a tiny tendril of fear still curled in my chest. "You must know that I can prove you created an entirely false identity."

Moriarty groaned in weary exasperation. "Oh, just kill yourself, it's a lot less effort." Then, perhaps recalling that I would tear away any argument with my logic, he switched to a pathetic appeal.

"Go on. For me." And then, in that blasted, grating, high-pitched squeal: "Pleeeeeease?"

My hands flew from my pockets to grasp his collar – I would _not _touch this man – and shove him away, leaving him half hanging over the street, only my will to keep him from falling.

"You must be insane to think I would even consider it."

"You're just getting that now?" he asked, blinking as though astonished that logic hadn't detected that earlier. "Yeah, yeah, don't tell me, Jimmius Assius or some such public school nonsense."

No fear in his eyes or in his tone. Not good.

In fact, Moriarty was grinning, _grinning!_, despite his suddenly-precarious situation – or perhaps because of it. "Okay, let me give you a little extra incentive," he told me. Incentive? "Your friends will die if you don't."

In my shock I almost let go. He would have fallen to his death and he would have laughed, but instead I pulled him back to safety because the last thought I had before my mind stopped working told me that there would be more to this.

But. . . No. No, no, no. This was not how logic was supposed to work. There was always an answer, a solution, a means that involved order, rules, not John. . .

Damn it all, Moriarty could probably read their names in my eyes. "Not _just _John," he said, his voice dropping to an obscene whisper, "even though I'm sure that would be enough. _Everyone. _ Three bullets. Three gunmen. Three victims. There's no stopping them now, unless my people see you jump."

"Ad Misericordiam," I whispered, but m- my heart – which had just recently been proven to exist – was not in it at all. That treacherous organ suddenly felt like it was pounding against my throat.

"Ah, that one I do know," Moriarty said gleefully. "People try it on me all the time. 'Oh, Jim, don't let them kill me with that particular set of knives, why? because I have a family at home and they'll starve if your men carve your name in my stomach, oh God aaaagggh. . ."

He paused as if waiting for me to add the insight, but I was in no state to do so. My mind was running through the different logical applications to this scenario, and responding more and more sluggishly as it could provide no ready answers. . .

After a brief pause of gleeful clinical evaluation, Moriarty added the explanation himself with considerable relish.

"It's a fallacy because there's no argument, Sherlock. They don't answer my question and instead try appealing to the sympathy that I just don't have. I just _love _Ad Misericordiam. Do you understand that one, Sherlock, _really_ understand it – enough to see how it's not going to work here?"

"John- You can't involve others," I mustered. "They have nothing to do with the Work, that's like setting a city on fire to destroy a single home. . ."

"False Analo_gy_," Moriarty sang. "The situations are entirely different – you can't make a proper comparison between the two. This logic thing is_ fun_, I can see why you _liked _it!"

Oh. . .

"And why so much emphasis on Johnny-_boyyy_? Finally get up the gutsto ask him something _important_, or was he the one who asked _you_?"

I should have known he would pick up my mistake. Stupid, to have let John's name slip out first!

Moriarty must have seen some hint in my face: his smile stretched wider. "I'm _jealous_, honey, but, oh, we can fix _that_! Tell me, what did he say? You have to work with me here, I need to know what turns you on. Tell me, or he'll have to."

"John would never betray me," I blurted out.

"Uh-oh – Dicto Simpliciter," Moriarty said, slowly, as if surprised. "Sherlock, I thought you knew your logic better than that! But that's a _fearfully _unqualified generalization: how do you know Johnny-boy won't talk? Has he ever been faced with that kind of choice before? Would his experience matter if we applied a little pressure to the right spot – that shoulder, for instance, or that leg?"

The thought of some faceless devil torturing John caused a strange sensation in my chest: for a brief blurry second it felt as though my heart skipped a beat of the normal cadence. Logically, I knew it couldn't have happened – but it felt like it had.

"He wouldn't. He may not – _understand_ – everything that is happening, everything that I told him, but he- he promised me that he would never leave. It is clear that – that _something_ has changed."

"Hasty Generalization!" Moriarty crowed. "You're basing this grand conclusion on a handful of words you wrung from a man in shock _one night ago_? He could be packed up and off by tonight when he recovers his senses, or he could be sitting at home waiting to wring your neck for looking at him sideways!"

"But – I observed a slight flush of color to his face when he said it, and he was certainly startled," I protested. "The connection is obvious, the feeling was reciprocated-"

"Slightly Post Hoc of you, isn't it?" Moriarty asked rhetorically. " 'Ooh, Johnny-boy's _blushing_, that must means he's aroused, it couldn't mean he's embarrassed or disgusted, no'. . . I'm seeing a definite fallacy of connection here, Sherlock. If only you could see yourself, really, and how far you've fallen – really, what are a few more stories going to add to a mess like _this_?

I didn't mean to say it, I don't know where it came from, I certainly had never admitted it even to myself and yet here I was telling this creature.

"It means that John loves me, despite everything that I am and everything that he said he was!" I cried.

Moriarty's eyes gleamed, and it was then that I knew, no No NO I knew what he was going to say, and he knew that I knew. . .

"Why, Sherlock, I do believe that is a Contradictory Premise," Moriarty said slowly, drawing the sentence out as if surprised to find it in his mouth. "If a man is _heartless_ – let's just use you as an example, purely hypothetically of course – how can anyone, least of all some ramrod-arsed _tin_ _soldier_, really expect to be _loved _by him?"

I felt light-headed – why did I feel light-headed, John? – Moriarty must be right, blast him, of course, my conclusions had been based on emotion and desire rather than logic – and you would hate me for this, John, even if you were too noble to actually say it – one day I would wake up and you would be gone – see what happened when one didn't follow the dictates of logic – _John_

I stepped up to the ledge and looked down. Molly's people were not in position yet, and the truck that would carry me into hiding where I could destroy the spider's web was still down the street.

I stepped off anyway.

Logic said it was the only thing to do. My 'love' was a fallacy.

* * *

**_I'm sorry, it's the only logical ending I could see, don't hate me. . . Or, ok, fine, I'd hate me too, but tell me why!_**

**_And, ugh, I do _****not****_ enjoy writing as Moriarty. Thank God most of it was already done for me. _**


End file.
